Treatment of sylvinite ore



Patented Nov. 19, 1940 UNITED STATES TREATMENT or SYLVINITE ORE Arthur J. Weinig, Golden, 0010., assignor to Potash Company of America, Denver, 0010., a

corporation of Colorado No Drawing. Application April 15, 1938,

. Serial No. 202,208

11 Claims. (01. 209-166) This invention relates to a froth flotation process for the separation of the valuable constituents of sylvlnite ores.

Sylvinite ore consists mainly of sodium chloride and potassium chloride crystals, together with minor inclusions of other mineral matter, such as iron and manganese oxides, clays, poly= halite and the like.

The invention relates particularly to the separation of the various salts of the-ore to the end that potassium chloride may be recovered as a substantially pure product and it is an object of the invention to provide a simple and inexpensive treatment by which various constituents other than potassium chloride solids are selectively floated in a froth leaving the non-floated solids of the treatment as a purified potassium chloride product.

In such a flotation treatment the pulp-forming step includes the introduction of finely-divided particles of sylvinite are into a saturated solution of the ore to prevent dissolution of the mineral particles. Such a pulp-producing operation has beendisclosed in Anderson Patent In practicing the present invention the pulp formation operation dlifers from the treatment of the Anderson patent in the inclusion in the solution of the pulp of a catalyst capable of pro- 39 moting a flotation reaction for sodium chloride.

To this end metallic lead or lead salts are entered into solution in the liquid phase of the pulp, which feature is described and claimed in my co-pending application Serial No. 173,431,

35 filed November 8, 1937 for Flotation process, and

the liquid phase difiers from the saturated solution of the Anderson treatment as a consequence.

Another object of the pesent invention is to provide a class of flotation reagents for use in 40 a froth flotation separation of the valuable con stituents of sylvinite ores, which require but little dilution with water to be efi'ective, and thereby improve the degree of washing allowable on the concentrate of such a treatment by permit- 45 ting use of additional quantities of liquid for this purpose when the liquid phase of the treatment is recirculated through the process.

The class of reagents referred to consists of organic acids classed as alicyclic carboxylic acids 50 involving ring structures and which correspond empirically to the formula CTZHZfl-ICOOH, the entire range of compositions in this class being eflective for the purposes of the present invention. The salts of these acids also are generally efiective. These compounds can be made syn- 5 thetically in many ways and are extensively produced in the petroleum industry. Examples of the naphthenic acid group suitable for the purposes of the present invention are described hereinafter. 10

Various derivatives of the naphthenic acids are also suited for use as reagents in the present treatment and examples of such derivatives are the alkali naphthenates and more particularly sodium and/or potassium naphthenates, 15 the ammonium naphthenates and more particularly ammoniumnaphthenate, and organic base naphthenates and more particularly triethanalomine naphthenate.

For convenience in description, the entire class 2 of such acids ad salts will be designated by the formula CnHBn-ICOO-R, in which R may be hydrogen or a base, either organic or inorganic.

When reagents of the aforesaid classifications are used in the pulp of the present invention they 25 exert a selective amnity for the sodium chloride solids and the insolubles such as polyhalite and the gangues, with the result that such constituents collect in a froth leaving the residual solids as a purified potassium chloride product which may be separately removed.

These reagents produce frothing, collection, promotion and selection in a froth flotation treatment of sylvinite ores in which lead is dissolved.

In addition to their use as the sole flotation reagent of the treatment the naphthenic acids and derivatives may also be used effectively with the fatty acid and alkali resinate reagents descrimd in my aforesaid application Serial No. 73,43 40 and more particularly with oleic acid, palm kernel soap, coconut oil soap, and. the alkali resinates described in my Patent No. 2,105,295, and with the aforesaid reagents in combination with cresylic acid, as described in my co-pending application Serial No. 123,484, or with cresylic acid alone.

When used in the mixtures aforesaid the naphthenic acids and derivatives are effective in reducing the quantity of a given reagent compocharacteristics of the ore and other factors,

grinding to 48 mesh ard.

- The ground ore is entered into a solution saturated with respect to both sodium chloride and potassium chloride and preferably a saturated solution of the ore, and prior to commencement of the fiotationaction the lead, which serves as the catalyst, must be present-in such saturated solution.

Any of the well-known methods of dry or wet grinding may be employed. and in practice it has been found that good results will be elected by wet grinding in a pebble mill in closed circuit with a classifier. In such an operation it is preferable to enter the catalyst into solution in the grinding circuit, although it may be otherwise introduced where desired, and from 1 to 2 grams of lead per liter in the solution is recommended for best results.

The pulp'so formed is entered into suitable froth flotation apparatus and subjected to a flotation treatment in the presence of any of the aforesaid reagents or reagent mixtures which may be mixed initiallywith the pulp before being subjected to the agitation and aeration of the flotation treatment, or where more convenient, the reagent may be introduced into the flotation cell separately from the pulp and mixed therewith by the agitative action of the process.

In the treatment the sodiinn chloride and gangue constituents in suspension separate from the potassium chloride content and collect in a froth which is discharged from the tank by overflow or in any other suitable manner, while the purified potassium chloride solids are collected as a non-floated concentrate and separately removed.

While I do not wish to belim'ited toany exact proportions in'the use of the substances comprising the reagent, satisfactory results have 68 been obtained by the use of .from V to 1 pound :o'f magphthenlc acid or its equivalent "in .its salts per ton of ore. The detergent powers "of the inaphthen'ic acid reagents .are very low while the brine "solubility of these compositions is :much

my be taken as a stand- ;for'which reason they are much more diiiicult ito :salt out than the soaps.

3T0 iaiford a better understanding of ithe operwiting procedure certain test'operations now be cited. In these tests, sylvinite iore from the iCarls'bad, New Mexico field :were subjected to itreatment. Gin analysis this are shown to 46% potassium chloride.

The general procedure for these tests involved the introduction into a flotation .machine of a ipulp composed of one part by weight of such tore, ground to 48 mesh, and .three parts by weight of .a saturated solution of the sylvinite ore, containing two grams-of lead 'per litre.

78 This pulp was then subjected to aeration and higher than any of the soaps heretofore used.

.(A) Narnmnmc Acme (Comm) REAGENT Reagent use:

.54 lb. for the first froth .28 lb. for the second froth Metallurgical results of test Perler- Per- Percent cent cent cent weight K01 NaGl insol.

First iroth-.- 41.2 9.95 87.7 2.29 Second froth. 18.5 84.00 63.4 1.68 Unfioated residue -l 40. 3 01. 50 a. 3 10 (B) some Narn'rrmns'm Reagent use:

.30 lb. sodium naphthenate for first froth .20 lb. sodium naphthenate for second froth Metallurgical results of test Per- Per- Per- Perce'nt cent cent cent weight K01 NaOl ,insol.

Firstfroth see 7.1 00.1 224 Second froth 14.3 19.9 73.7 1.46 Unfloatod residue 48.9 87.0 12.6 0.46

(G) AMMoNrtm NAPHTHENATE Reagent use:

.40 lb. for first frot .40 lb. for second froth Metallurgical results of test Percent Percent Percent 53'; weight K01 N801 ML First froth .J 44.5 12.3 85.5 2.15 Seoondiroth 18.8 40.5 58.0 1.41 Unflostedresidua.. 36.7 92.4 6.0 .73

(D) 'Tars'rnANoLAmNE Nsrnrnmn'm Reagent use:

.40 lb. of first froth .60 lb. for second froth Metallurgical results of test Percent Percent Percent weight K01 N801 3 First'froth sale 4.9 92.3 2.76 Second froth "24.0 25.9 69.7 1.37. Unfloated residue 42.2 89.6 9.9 0.45

While the foregoing tests disclose an efficient separation, the final grade and recovery may be improved appreciably by treatment of both froth and residue products of the initial separation, preferably by temperature variation methads of the type described and claimed in my Patent No. 2,105,294.

For example, an identical test was made by flotation as shown in Test (A) in which a meastated with the remainder of the solution not used in the flotation operation, and heated to 40 C. The warm pulp was then settled and iiitered. The warm solution thus recovered was added to the unfioated residue pulp and the resulting pulp was then cooled down to 20 C. with agitation. After this, the cooled pulp was settled and filtered. Following these operations, the filter cakes of sodium chloride and potassium chloride were washed with saturated aqueous solution of sodium chloride and potassium chloride, respectively, in volume amounts which when these wash filtrates were added to the cooled filtrate from the potassium chloride pulp, restored the volume of the original quantity of solution used at the start of the mt.

This gave the following metallurgical result:

Percent Percent Percent weight K01 recovery Sodium chloride and gangue reject". 54. 0.6 KCl product 46. 0 99. 0 99. 4

Many advantages result from treatment according to the present invention. The reagents are very cheap compared with the costs of other reagents referred to hereinbeforeand an abundant supply exists in American petroleum insuring adequate supply in the event of national emergency.

Further, when used in plants where pure water is not available, the present reagents eliminate the necessity of any considerable shipment of pure water to such plants, as naphthenic acids and their salts require either no water at all, or very little water for dilution, when they are introduced as flotation reagents.

The increased capacity previously mentioned results from the fact that the flotation treatment is shortened by reason of the greater selectivity of the reagent, and the treatments subsequent to flotation are likewise shortened and improved due in part to the absence of water ordinarily used for soap dilution, which in the present instance permits addition of extra wash liquid without producing an increasing volume of mill solution.

In a treatment of this character, it is highly desirable to recirculate the saturated solution to avoid wasting the valuable constituents in solution, and to avoid the expense and loss of time incident to the production of such a solution. When the reagents of such a treatment have to be diluted, the amount of water added with the reagent must be compensated for by withdrawal of an equivalent quantity of saturatedsolution. Therefore, the present process provides an improvement in operating procedure due to the small amount of water required for reagent dilution, in that a greater volume of liquid can be employed in washing the separated salts to improve grade and recovery, without thereby increasing the volume of the recirculating solution.

In introducing the lead into the solution, as previously described, metallic lead may be used and introduced into the grinding circuit, or if preferred, lead salts may be used and introduced either into the grinding circuit or elsewhere as preferred. Examples of such salts are lead acetate, lead nitrate, lead sulfate, lead carbonate, lead chloride, and lead oxide. The lead is not dissipated in the flotation reaction and an occasional addition to compensate for mechanical losses is all that is required as has been explained in my aforementioned Patent No. 2,105,295.

While the various steps and treatments hereinbefore described disclose what in practice has given highly efiicient results in the separation of valuable constituents of sylvinite ores, it will be apparent that changes in the operating procedure and in the various steps and treatments may be availed of without departing from the spirit of the invention as herein set forth, and it will be understood that the various phases of the oper-' ating procedure are cited merely for the purpose of illustrating the invention and not for the purpose of defining-the limits thereof, reference being had to the appended claims for this purpose.

What I claim. and desire to secure by Letters Patent is: Y

1. The process of treating sylvinite ores, which comprises introducing sylvinite ore in finely di- .vided condition into asaturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp by the action of naphthenic acid or a salt thereof.

2. The process of treating sylvinite ores, which comprises introducing sylvinite ore in finely divided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potassium chloride present by the action of an alkali naphthenate.

3. The process of treating sylvinite ores, which comprises introducing sylvinite ore in finely divided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potassium chloride present by the action of sodium naphthenate.

4. The process of treating sylvinite ores, which comprises introducing sylvinite ore in finely divided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potassium chloride present by the action of ammonium naphthenate.

5. The process of treating sylvinite ores, Which comprises introducing sylvinite ore in finely divided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potassium chloride present by the action of an organic base naphthenate.

6. The process of treating sylvinite ores, which comprises introducing sylvinite ore in finely divided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potascomprises introducing sylvinite ore in finelydivided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potassium chloride present by the action of a mixture of naphthenic acid or a salt thereof and an alkali resinate.

9. The process of treating sylvinite ores, which comprises introducing sylvinite ore in finely divided condition into a saturated solution of the ore containing lead dissolved therein to form a pulp, and froth floating sodium chloride and gangue constituents of the pulp from the potassium chloride present by the action of a mixture of naphthenic acid or a salt thereof and cresylic acid.

10. In a process for treating sylvinite ores in a saturated solution of the ore in a cyclic operation, involving a froth flotation separation of the sodium and potassium salts of such ore, followed by separation of the liquid and solid phases of the products of such flotation separation, washing of the solids so separated, and the return of the liquid phases so separated to the flotation stage,

the improvement which comprises the use of naphthenic acid or a salt thereof as reagents in the froth flotation separation, in the presence of' lead or a salt thereof thereby increasing the naphthenic acid.

ARTHUR J. WEINIG. 

